Thermostatic control for water heaters



June 17 1924. 1,498,202

- I ll L. REID THERMOSTATIC CONTROL FOR WATER HEATERS Filed Sept. 30, 1921 Jan 6a? L, Rea/ 00 Patented June 17, 1924:.

PATENT OFFICE,

DAVID L. REID. OF DETRQIT. MICHIGAN.

THEB IVIO STATIC CQNTROL- FOR Application filed September 30, 1921. Serial No. 504,491

To all whom it may concern:

Be it known that 1,. DAVID L. Run), a citizen of the United States: of America,1residing at'Detroit. in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Thermostatic Controls for ater Heaters, of which the following is a specification, reference being had therein to the accompanying drawings. v g

This invention relates to thermostatic controls for water heaters. I i

It is the object of the invention to provide a, simplified and positive thermostatic control mechanism for automatically regulating the supply of gas to a water heater according to the resulting temperature.

In the drawings I Figure 1 is a diagrammatic view of an improved apparatus, the thermostatic mechanism and the water tank being shown in section.

Figure 2 is a sectional detail of the adjusting means for the thermostat, the section being taken on line 22 of Figure 1.

Figure 3 is a section through a fitting employed in the mechanism.

In these views the reference character A designates a hot water tank and B a pipe for delivering the heated water to said tank. Said pipe includes a coil B beneath which is disposed a gas burner C. Gas is delivered to said burner by a pipe having the portions C and C the former discharging into a rectangular metallic casing D and the latter leading from said casing to said burner. Within said casing there is rigidly secured an annular fitting E, which has an exteriorly threaded reduced portion E that extends downwardly through the bottom of the casing that is connected to the pipe G For retaining the fitting E in firm engagement with the bottom of the casing D, I preferably provide a suitable lock nut E that is threaded onto the reduced portion E of the fitting and that engages the lower face of the casing. The top end of said fitting is conically beveled to form a seat engageable by a correspondingly shaped valve F pivotally carried by the long arm G of a bell crank having a short downwardly pro jecting' arm H. Said bell crank is pivotally mounted at the juncture of its arms as indicated at Q upon a lug J integrally projecting from the inner end of a plug K mounted in an end' wall of said casing. ssicr plug has a screw threaded outer end portion which is tapped into the wall of thetank A and suitably sealed in said wall. Said plug rigidly carries a tube L of copper or a like metal which is readily responsive to variations of ten'iperature, saidtubeprojecting radially into said tank. Within said" tube is centrally disposed a rod M of iron or a like metal which is relatively unresponsive to variations of temperature, the outer extremity of saidrod being rigidly sealed within the free end; of the tube L. Said" rodj atits other extremity is axially sli'dabl e within the plug K, projecting beyond the innerend of said plug. N is a set screw adjustably carried by the short arm H of the crank and arranged to bear against the adjacent projecting end of the rod M in substantial alignment with said rod. To insure said screw being held fixed in any desired position of adjustment, the arm H is split downwardly from said screw and the bifurcations thus formed are clamped upon the set screw N by a screw P engaging the free ends of said bifurcations.

Discussing the operation of the mechanism as so far described, it is to be under stood that the set screw N is adjusted with relation to the rod M to normally maintain a predetermined temperature in the tank A through regulation of the gas supply to the burner C. Thus any increase of temperature in said tank above the predetermined point will result in an increased expansion of the tube L which owing to the nature of said tube and the rod M will produce a slight shifting of said rod into said tank, this will permit a swinging of the bell crank, due to the weight of the valve F, shifting said valve toward its seat and reducing the supply ofgas to the burner C. Similarly a reduction of temperature in the tank A below the predetermined limit owing to the resulting relatively large contraction of the tube L, shifts the rod M toward the bell crank rocking the latter to unseat the valve F and admit more gas to the burner. It is to be observed that the bell crank has the effect of considerably multiplying the movement of the valve resulting from any movement of the thermostatic rod M.

To permit the valve F to normally be fullyseated, if desired, without extinguishing the flame of the burner there is provided means for constantly maintaining a pilot flame at the burner independently of the thermostatic control. Thus the fitting E is integrally formed within the casing D with a lug Q in which is formed a restricted by-pass K for admitting gas from said casing to said fitting below the valve seat of the latter. As a provision for regulating the flow of gas through said by-pass an adjusting screw S is tapped into said lug and is adjustable to more or less obstruct the by-pass.

Among the desirable features of the de scribed invention may be mentioned the absence of any springs to necessitate adjustment or replacement and an absence of any valve stems requiring packing, furthermore the construction is one that may be readily installed in connection with a gas water heater or range boiler already in use. The construction serves to maintain a constant supply of hot water ready for useand water in the tank at the predetermined temperature. V

What I claim as my invention is 2- In a device of the class described, the combination with a casing having a gas inlet and a gas outlet, and valve for regulating the passage of gas through said outlet, of control means for said valve including a plug mounted in a wall of said casing, a lug projecting from the inner end of said plug, a bell crank lever pivotally mounted at the juncture of its arms upon said lug,

the long'arm of said lever being connected to said valve, a tube carried by said plug, said tube being readily responsive to 'temperature variations, a rod within said tube, said rod being relatively Lin-responsive to temperature variations, the outer end of the rod being sealed within the free end of the tube, said rod atits other end being axially slidable within said plug, and a set screw adjustably carried by the short arm of said lever and arrangedto bear against the adjacent projecting end of said rod.

In testimony whereof I afiix my signature.

DAVID L. REID. 

